The present invention relates to a pixel defect correction device using a solid-state imaging device (element) and an imaging system using the same.
Pixel defects in a CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor) or other solid-state imaging device (element), or an imaging system (also described as a “camera apparatus”) using the same, can be classified into two types; crystal defects occurring before the shipment as in the manufacturing process and secondary defects which occur after the shipment. Various defect correction methods have been proposed to prevent image deterioration caused by these defects.
For example, secondary defects which may develop after shipment of a solid-state imaging device (element) or imaging system are on the rise as a result of higher pixel densities achieved in solid-state imaging devices (elements). Therefore, dynamic defect detection and correction methods are popular as there are no limitations to the correction count.
In a dynamic defect detection or correction of a solid-state imaging device (element) or imaging system, however, discrimination between high frequency components and pixel defects involves considerable difficulties. As a result, a high frequency component may be mistaken for a defect. Such a determination leads to overcorrection, erroneously eliminating a line or point which should exist from the image if such a letter or point contains a high frequency component.
For defect correction of a solid-state imaging device (element) or imaging system, it is common, at the time of shipment, to clamp the luminance level and perform detection and correction statically with light completely blocked or light of a given luminance admitted because this suppresses erroneous detection or correction.
For secondary defects of a solid-state imaging device (element) or imaging system, it is common to perform dynamic detection and correction without limiting a correction count because of secondary defects on the rise as a result of higher pixel densities achieved. Moreover, setup change or readjustment after the installation is difficult depending on the installation location of the imaging system.